With the development of science and technology, there are more and more types of electronic devices, whose functions are more and more powerful.
At present, electronic devices adopting direct current supply in the market mainly use DC-DC power supplies (“DC” is short for direct current) to supply power. If voltage outputted by a DC-DC power supply jitters, this will make a load circuit work improperly or even damage a load circuit. For example, in many in-vehicle electronic devices, due to existence of a super-capacitor of an input end of a DC-DC power supply, following cases will be present in the process of power failure of the DC-DC power supply: a voltage across the super-capacitor of the DC-DC power supply decreases, the DC-DC power supply is turned off when the voltage across the super-capacitor is smaller than the minimum working voltage of the DC-DC power supply, the voltage across the super-capacitor may be rebounded after the DC-DC power supply is turned off; and the DC-DC power supply is turned on again when the voltage across the super-capacitor is rebounded to the minimum working voltage of the DC-DC power supply. A load is increased after the DC-DC power supply is turned on, which makes the voltage across the super-capacitor drop to be less than the minimum working voltage of the DC-DC power supply again, thereby causing the DC-DC power supply to be turned off again, the voltage across the super-capacitor is rebounded again after the DC-DC power supply is turned off; and the DC-DC power supply is turned on again when the voltage across the super-capacitor is rebounded to the minimum working voltage of the DC-DC power supply. It is repeated many times in this way. In the above process, the output voltage will fluctuate since the DC-DC power supply is repeatedly turned on and turned off, which has a great negative effect on the load.
At present, no related technical solution can effectively solve the problem of repeated turn-on or turn-off of the DC-DC power supply caused by fluctuation of the input voltage of the DC-DC power supply in the vicinity of the minimum working voltage of the DC-DC power supply.